The present invention relates rupture valves. More particularly it relates pilot operated rupture valves.
Rupture disks have been found to be inaccurate as to the actual rupture point, notwithstanding the rated rupture point, as much as 50% off. In order to improve the reliability of rupture disks, the present invention is a device that allows the rupture disk to operate at over 90% accuracy of the rated rupture point.
Briefly the present invention is a rupture disk assembly comprising two rupture disks, a chamber between said disks, a first line in fluid communication between said chamber and the interior of a vessel on which said rupture disk assembly is functionally mounted, a valve in said first line to reduce the pressure in said chamber to less than 90% of the pressure of said vessel, a second line in fluid commuication with said vessel and a pilot valve, and a third line in fluid communication from said chamber to said pilot valve, whereby the pressure in said chamber is static and said pilot valve is closed while the pressure in the vessel is at or below the set pressure of the pilot valve and whereby a fluid flow is established through said chamber when said pressure in said vessel exceeds the set pressure of said valve. Preferably a pressure reduction valve is located in the line between the chamber and the pilot valve to prevent backflow from the pilot valve to the chamber.